This invention relates to packaging, and more particularly to a vacuum packaging apparatus and method.
Vacuum packaging is typically employed for perishable products in order to minimize contact of the perishable product with air, which generally serves to prolong the shelf life of the product. In the past, vacuum packaging machines for perishable products such as processed meats, primal meat cuts, cheese blocks and the like, have involved transporting the products on a plate-type conveyor that travels in a circular path, and utilizing a rotating carousel-type evacuation system for evacuating and sealing the product package as the product is moved on the conveyor. In a carousel-type evacuation system of this type, a vacuum head is mounted at the end of each of a series of arms that extend radially outwardly from a rotating hub. Each vacuum head is rotated and lowered into contact with one of the conveyor plates, to enclose the product. As the conveyor advances the product in an arcuate path, the interior of the vacuum head is exposed to negative air pressure to evacuate the package, and the evacuated package is then sealed around the product. When the conveyor and the vacuum head reach a predetermined position, the vacuum head is raised off the conveyor and the product is discharged or removed from the conveyor plate.
The above-described vacuum packaging system presents a number of drawbacks. For example, the vacuum and sealing apparatus is a complicated mechanism that requires control of both rotational and vertical movement, which is difficult to accomplish. The apparatus requires a large number of vacuum heads, and requires the use of multiple long vacuum hoses to convey negative air pressure to the vacuum heads. This requires movement of a large quantity of air in order to evacuate the vacuum heads, which significantly decreases efficiency of operation. This type of vacuum and sealing apparatus involves a large number of moving parts, which results in high maintenance and repair costs. In addition, the layout of a vacuum and sealing apparatus of this type requires a significant amount of floor space.
It is an object of the present invention to provide a vacuum packaging system that avoids the drawbacks associated with the carousel-type vacuum and sealing apparatus of the prior art. More specifically, it is an object of the present invention to provide a vacuum packaging system that involves a simple linear, reciprocating motion rather than the rotational motion involved in a carousel-type apparatus. Another object of the invention is to provide such a vacuum packaging system that involves a significantly reduced number of moving parts, in order to simplify operation and to reduce maintenance time and cost. Yet another object of the invention is to provide a vacuum packaging system that has a relatively compact arrangement of components, and therefore occupies a relatively small footprint on the floor. A further object of the invention is to provide such a vacuum packaging system which enables efficient movement of air during the evacuation operation, and avoids the use of long vacuum hoses associated with prior art vacuum packaging equipment. A still further object of the invention is to provide such a vacuum packaging system in which it is relatively easy to position guards around the exposed, moving components of the system. Yet another object of the invention is to provide such a vacuum packaging system in which the various steps involved in the vacuum packaging process are carried out in a simple, efficient manner while providing highly satisfactory operation in forming a vacuum package.
In accordance with one aspect of the present invention, a vacuum packaging apparatus, includes an article carrier having a series of linearly movable article supports, each of which is adapted to support an article contained within an open receptacle, and a linearly movable evacuation arrangement that includes one or more evacuation chambers. The evacuation arrangement is operable to move each evacuation chamber into engagement with one of the article supports so that the article is contained within the evacuation chamber. The evacuation arrangement is further operable to move the evacuation chambers along with the article supports and to sequentially evacuate and seal the receptacle during movement of the article supports and the evacuation chambers together. The linearly movable evacuation arrangement includes a series of evacuation chambers and a reciprocably movable drive arrangement that is configured and arranged to move the evacuation chambers between an upstream position and a downstream position. Each evacuation chamber is operable to evacuate and seal a receptacle contained on one of the article supports as the drive arrangement moves the evacuation chamber from the upstream position to the downstream position. The drive arrangement is further configured and arranged to selectively move each evacuation chamber toward one of the article supports for engaging the evacuation chamber with the article support, and to selectively move each evacuation chamber away from the article support to disengage the evacuation chamber from the article support.
In a preferred embodiment, the article supports face upwardly between the downstream and upstream positions of the evacuation chambers, and the drive arrangement is operable to sequentially lower each evacuation chamber onto one of the article supports, advance the evacuation chamber along with the article support while the evacuation chamber evacuates and seals the receptacle, and raise the evacuation chamber away from the article support. The drive arrangement includes a horizontal drive for advancing the evacuation chambers horizontally along with the article supports, and a vertical drive for raising and lowering the evacuation chambers relative to the article supports. The evacuation chambers may be carried by a carriage that is movably mounted to a frame located adjacent the article carrier. The horizontal drive moves the carriage horizontally relative to the frame and the vertical drive moves the evacuation chambers vertically on the carriage.
In accordance with another aspect of the present invention, a vacuum packaging method includes the acts of placing an article, contained within an open, sealable receptacle, on one of a series of article support members; linearly moving the article support members to advance the articles supported by the article support members; engaging one or more evacuation chambers with one or more of the article support members; linearly moving the evacuation chambers along with the article support members while supplying negative air pressure to the evacuation chambers within which an article is disposed, to evacuate the receptacles containing the articles; sealing each receptacle about the article contained therein while the receptacle is evacuated within the evacuation chamber; and disengaging the evacuation chambers from the article support members. Details of this aspect of the invention are substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.